Conveyer



Feb. 21, 1928.

' G. E. WOODWARD CONVEYER Filed NOV. 13, 1925 2 Sheets-Sheet 1 Feb. 21,1928. 1,659,968

G. E. WOODWARD CONVEYER Fild Nov. 13. 1925 2 Sheets-Sheet 2 ma a Feb. 21,1928.

GEORGE E. WOODWABD, OF BOSTON, HABSAQHUBETTB.

convnrna."

Application filed November 18, 1925. Serial No. 88,889.

This invention relates to a safety device for inclined conveyers and particularly for type, to prevent the escalators.

The invention has for its object to provide an eflicient, simple and relatively inexpensive safety device for inclined conveyers and particularly an escalator of the ascending eccalatorwfrom descendunder all conditions of use in the event of the reversal of the chain designedly or by accident as in case of breakage, and to thereby prevent injury to the passengers upon,the escalator.

To this end the safety device is provided with a circuit controller which is positively closed and positively opened by means rendered active and inactive by movement of the escalator chain in OPPOSltG' directions .under all conditions of use.

The circuit controller governs the circuit of an electromagnet, which is employed to hold a chain-engaging member out of contact with the chain under normal conditions of use, and said electromagnet is operatively connected with an actuating device which is connected with preferably a pluralit of chain-engaging members, so as to enab e the chain to be en aged by a plu rality .of said members simu taneous y when under all conditions of use the chain as a whole is reversed, or a part thereof is reversed as when the chain is broken.

The common actuating device is moved in one direction into an inactive position by the electromagnet, and is moved in the opposite direction into its active position, preferably by a spring, and said actuating device is connected with the chain-engaging members so as to permit them to be out of contact with the chain when the latter is intact and operating normally.

The chain-engaging members are preferably made as dogs or pawls pivoted to stationary supporting members, which, offer rigid abutments to prevent reverse move ment of the chain atter the said members have been engaged wlth the chain.

The electromagnet may and preferably will be included in the circuit supplying power to the motor shaft for driving the chain and for applying the brakes to the motor shaft in the event of chain breakage,

so that the circuit controller responsive to the movements of the chain governs the operation of the motor, the brakes'co-operating therewith and the electromagnet which controls the operation of the chain-engag- 7 ing members independently ofthe latter as will be described.

These and other features of the invention will be hereinafter described and particularly defined the claims at the end of this I troller and a mechanism for operating the same by reversal "of the chain; Fig. 4 is a plan of a portion of theescalator shown in Fig. 1; Fig. 5 is a wiring diagram illustratingthe electrical circuits utilized in connection with the present safet devices; and. Fig. 6 is a detail in end e evation of the mechanism illustrated in Fig. 3.

' The difieren tf features of'the present invention while applicable'to different forms of inclined conveyers in which it is desirable to preventd'escent of the conveyer in the event of chain breakage, are primarily deslgned for use 1n connection with escalators used to convey passengers from different levels, and which at the present time are used in subways, elevated structures, stores and the like. The general construction of such escalators is well-known, and for the purpose of illustrating the present invention, the escalator may be regarded as comprising anendless cham 10 adapted to travel over an up er splrocket 12 and alower sprocket 13, 0th t e sprockets 12 and 13 being suitably journaled' in a'framework 14 by which the escalator is supported. The chain '10 has operatively connected therewith,

tread members 15 upon which the passengers stand in being conveyed either from a lower to a higher level, as in the case of an ascending escalator, or from a higher to a lower level as in the case-of a descending escalator. Thee scalator is driven by an electric motor represented diagrammatically at 16 in Fig. 5, which is connected through suitable gearing to theupper sprocket 12. The construction and operation of the escalator per se may comprise that illustrated in the at-' Seeberger No. 1,025,316 or that us cut to trated' in the patent' to Banana. 804,266

thrown upwardly as will be described, en-

gage the axles or'pintles of the chain. The pawls 20 are provided with an integral lug 32 adaptedito contact with pin '33 projecting from the bracket24, when the pawls are in anupper or operative position, the pin acting as a stop to limit the upward movement of the pawl. The pawl is also rovidedwith afsecond' lug or arm 40 which Hepends "into and extends between the arms of a yoke42, formed in the end of a rod 44 mounted'to slide in a hole or bore in the bracket 24. The rod 44 is provided with a collar'45 pinned thereon and with a second collar'46 loosely mounted thereon. A coiled spring 47 is interposed between each of the collars and 46, the sprin embracin the rod 44' and operating .to hol the secon collar'46 in engagement with the lug or arm 40.

In accordance with the preferred form of the invention, the escalator is provided with a plurality of pawls 20 mounted in the manner described, and the several pawls 20 are preferably arranged to be actuated by a single orcommon mechanism, and for this urpose the several rods 44 are connecte by links'50, each provided with a turnbuckle 52 for enabling the proper adjustment of the individual rods to be made, to the end that the pawls 20 may all move in unison. The

lowermost rod 44 is connectedby a link 54 to a rod 56 comprising an extension of the core or armature of a solenoid represented diagrammatically'in Fig. 5 as at 60, and which may comprise any of the well-known types of solenoids now commercially obtainable upon the market. v

The rod 56 comprising the'forward extension of the armature of the solenoid is pro vided with a relatively heavy coiled spring 61 interposed between the face plate 62 of a housing 63 within which the solenoid is mounted, and a collar 64 adjustably secured upon the rod The. solenoid housing 63 is mounted upon a bracket 67 secured to the escalator frame. The. parts are arranged so that when the solenoid is energized, the rod 56 is moved by the solenoid to an extreme position to the left, viewing Fig. 1, in which the hea coiled spring 61 is compressed. At suc timethe several coiled springs 47 are'under should not contact with 56 by a nut and pin66.

practically 'no compression, permitting the Weight of the pawls 20 to cause them to drop down into an inoperative position, illustrated mal operation of the escalator, the pawls that the parts maybe maintained tion of maximum strength and of maximum safety. H

Provision is, made for deenergizing the solenoid 60 in the event of breakage of .the chain, and when the solenoid is thus deenergized, the heavy coiled spring 61 operating the chain in order.

in a oondithrough the collar 64 operates to cause movement of the connected rods 44 to the right, viewing Fig. 1, compressing the individual springs 47 surrounding each rod and moving the collars 46 against the arms 40 to cause the'pawls 20 to be swung on their pivot up into a positionwhere they will engage the pintles or axles'30 of the chain at different points along the upper or working run thereof, and operatin to hold the upper or Working run of the c ain from downward move- .ment. In this manner, in the event of chain breaka e, the working run of the chain carrying t 1e load is prevented from descending so that injury to the load is prevented. The solenoid 60 isdeenergized in accordance with the preferred embodiment of the invention by circuit-breaking mechanism, including a ratchetwheel 70, and a pawl 72 pivoted upon the end of a pawl arm 73 mounted upon a rock shaft'74 projecting fromand journaled in a housing 75 secured to the stationary rotates. The ratchet Wheel 70 is fast on the hub 78of the lower sprocket 13 ofthe escalator, and as long as the escalator is running in a normal condition, the ratchet wheel 70 rotates with the sprocket 13 in a clockwise direction, viewing Fig. 1, and the pawl 72 merely clicks idly over the teeth of the ratchet. closure for contacts 80, 81 controlling a circuit, see Fig. 5, in which is included the potential switch 92 and its holding coil 94, and during the normal operation of the escalator this ClIClllhlS .closed at. the contacts 80, 81, thus energizing the coil 94 and maintaining the potential switch 92 closed, thereby estab- 'The housing 75 comprises an enlishing the circuit in which the solenoid 60 is included, and maintaining'the safety mech anism in a position in which the pawls 20 are disengaged from the escalator chain. The contact 80 is carried by an arm 83 secured upon the inner end of the, shaft 74 so that the contact 80is directly connected to and is capable of movement with the pawl 72 and also. the .pawl arm 73. A spring 85 co operates with the arm 83 to positively'move the contact 80 into engagement with the con tact 81 and to hold. it in-its closed position,. the contact 81 comprising a fixed contact sev cured in a lug 86 projecting from one of the inner walls of the housing 75. As above stated, the solenoid circuit remains closed at the contacts 80, 81 during the normal operation of the escalator.

When however, breakage of the chain ocours, and which in practice would occur somewhere alon the upper or working run of the chain, in the case of an escalator of the ascending type, as herein shown, the lower portion of the chain withits load starts to descend. When this occurs, the lower sprocket 13 of the escalatoris caused to move in a direction reverse to its normal travel, or in other words in a counter-clockwise direction, viewing Fig. 1. The reversal ,o-fithe lower sprocket 13 in this manner operates to rotate the ratchet wheel 70 in a counterclockwise direction and the teeth of the ratchet wheel pick up the pawl 72 and cause the pawl arm 73 to rotate in a counterclockwise direction, viewing Fig. 1, thus causing the contact arm 83 .withinihe housing 75 to be swung to move the contact 80 away from the fixed contact 81 and thus positively and automatically open the circuit of the holding coil 94, which permits the potential switch 92 to be opened, thus deenergizing the solenoid 60 and permitting the heavy coiled spring 61 to operate in the manner above described to simultaneously throw 85 the individual pawls 20 up into operative position where the ends of the pawls engage the axles or 'pintles 30 of the chain and prevent further descent ofthe same.

Provision is also made for cutting ofi the 40 supply of current to the motor 16 and for -applying the brakes '90 to the motor shaft 91 whenever chain breakage occurs, and the circuit connections for accomplishing this result, are diagrammatically illustrated in i a Fig. 5.

The potential switch 92 may be of the standard now commonly used in connection with the control of electric motors, and inasmuch as the details of its construction and operation are well-known, further description thereof is omitted.

In order toapply the brakes 90 to the motor shaft 91, the winding of a solenoid 100 is included in the motor circuit. As long as current is supplied to the motor, the solenoid 100 is energized, operating to hold the brakes 90 out of contact with their brake drum 95 upon the motor shaft 91 against the compression of the coiled springs 102. When the 50 main motor circuit is deenergized by the opening of the main circuit breaker 92, the solenoid 100 is deenergized, permitting the coiled springs 102 to cause the application of the brakes. g In the event that the escalatorchain should break, throwing the pawls 20 into operative engagement with the chain, and if for some reason the motor circuit should not be opened when chain breakage occurs, then the pawls engaging the lower part of the broken chain will hold it from descent while the remainin pawls will be permitted to yield by the coile springs 47, permitting the upper portion of the broken chain to continue in operation until it runs off of the drivingsprocket.

From the above description, it will be seen thata plurality of the pawls 20 are actuated by a single or common device, and that both the pawls and their actuating device are out of engagement with the chain under normal operating conditions, thus preventing wear between these parts.

It will further be observedthat the pawls when engaged with the chain rigidly connect the chain with the brackets 2 1 and the frame of the escalator, so that reverse movement of the chain after engagement by the pawls is resisted by the stationary framework of the escalator.

Itwill also be observed that the circuit controller 80, 81 is positively and automatically closed and opened by means which are rendered active and inactive by movement of the escalator chain in opposite directions independently of the pawls or dogs and under all conditions of use, and that the pawls or dogs are engaged with the chain when the latter is reversed irrespective of whether the reversal is brought about by a break in i the chain or by accident or design.

While the preferred embodiment of the invention has been illustrated and described, it will be understood that the invention may be, embodied in the other forms within the scope of the following claims.

What is claimed is 1. An escalatorhaving in combination a conveyer member, a dog normally disengaged from said conveyer member, an electro-magnet co-operating with said dog to hold it in its disengaged position, a circuit controller governing the operation of said electromagnet, means for positively closing said circuit controller, and means for positively opening said circuit controller, said means being rendered active and inactive by movement of the said chain in opposite directionsindependently of said dog.

2. An escalator having in combination a conveyer member, a dog normally disengaged from said conveyer member, electromagnetic means co-operating with the dog for holding it in its inoperative position,

and, a circuit controller for said electromagnetic means responsive to breaking of the conveyer member for deenergizing said electromagnetic means and enabling the dog to be engaged with the conveyer member to hold the same from movement.

3. An escalator having in combination a con veyer member, electromagnetic means opcrative when energized to permit movement of the conveyer member during normal operation of the escalator and when de'energized for holding the conveyer member from movement in one direction, and a circuit controller for said electromagnetic means" responsive to breaking of the conveyer member for deenergizing the same at such time.

4. An escalator having in combination an endless escalator chain, a plurality of dogs spaced apart and located below the working run of the chain, a solenoid, connections be tween the solenoid and the several dogs whereby the dogs are held out of engagement with the chain when the solenoid is energiged, means for throwing the dogs into engagement with the chain when the solenoid is deenergized, and a circuit controller responsive to breakage of. the chain for deenergizing the solenoid at such time 5. An escalator having in combination upper and lower sprockets, anescalatorchain running over the sprockets, a plurality of dogs located beneath the working run of the chain, a solenoid operatively connected with said plurality of dogs for holding the latter out of engagement with the chain when the solenoid'ls energized, a spring for moving the dogs into engagement wlth the chain when the solenoid-is deenergized and a circuit controller responsive to brea a e of the chain for de-energizing the solenoi at such time, comprising a ratchet wheel mounted to turn with the lower sprocket, a pawl co-opcrating therewith to be moved upon rotation of the ratchet'wheel in a direction reverse to its normal rotation, a circuit controller adapted to be, opened u on such reverse movement of the pawl, an a spring to close said circuit controller upon normal rotation of the ratchet wheel. I 0

" 6. An escalator havin in combination a chain, a dog normally disengaged from the chain, electromagnetic means operative when energized to hold the dog in an inoperat ve position out of engagement with the chain, a circuit controller for the electromagnet c means responsive to breaking of the chain for deenergizing said el'ectromagneticmeans at such time, and a spring through which the electromagnetic means is connected to the do 'i' An escalator having in combination an endless escalator chain, means for driving the same, including an electric motor, an means for stopping the escalator in the event of chain breakage including a lurality of chain-engaging members space apart and mounted to be movable into and from an operative chain-engaging position, means for holding said plurality of members in an inoperative position out of contact with the chain during the normal operation of the escalator in one direction, and means rendered operative by movement of the chain in a reverse direction for opening the power circuit to the motor and effecting movement of said plurality of chain-engaging members into operative position.

8. An escalator having in combination an endless escalator chain, means for drivingv the same in an upward direction,- a plurality of holding members co-operatin with said chain and normally disengaged t erefrom, a common actuating device for said holdin members also normally disengaged from sai chain, means for moving said actuatingdevice in one direction to render said holding members inoperative while the endless chaln is moving in one direction, and'means rendered effective by movement of the chain in matically placed in a different condition by movement of the chain in a reverse direction under all COIldltIOIlS of use of said escalator.

10. An escalator having in combination an endless escalator chain, upper ,and lower sprockets engaged by said chain; an electric motor for driving said sprockets in one direct' on, and a circuit controller for said motor positively closed when one of said sprock ets is rotated in one direction, and positively opened when said sprocket is rotated in the reverse direction under all conditions of use. '11. An escalator having in combination an endless escalator chain, upper and lower sprockets engaged by said chain, an electric motor for driving said sprockets in one direction, and a circuit controller for said motor, means for positively closing said circuit controller rendered effective by rotation of said sprocket in one direction, means for pos tively opening said circuit controller rendered eflective by, rotation of said sprocket in the reverse direction under all conditions of use, and a holding dog co-operating with said chain to be engaged therewith when said sprocket is reversed.

12. An escalator having in combination an endless escalator chain upper and lower sprockets engaged by said chain, a dog normally disengaged from said chain, a stationarysupporting member for said dog, an electric motor for driving said sprockets in one direction, and a circuit controller positively tion under all conditions of use.

13. An escalator having in combination an endless escalator chain, an electric motor for moving said chain, a potential switch governing the' operation of said motor, a holding coil for said potential switch governed by the latter, and a circuit controller for said holding coil in circuit with said potential switch and co-operating with the escalator chain to be closed when the chain is moved in one direction upon closure of said potential switch, and to be automatically opened by reverse movement of said chain with the potential switch closed.

14. An escalator having in combination a conveyer member, an electric motor formoving said conveyer member, a dog normally disengaged from said conveyer member, an e'lectromagnet co-operating with said dog to hold it in its disengaged position, means for engaging said dog with the conveyer member when said electromagnet is deenergized, a potential switch governing the circuit of said electromagnet and said motor, a holding coil for said potential switch, and a circuit controller for said holding coil co- 0 erating with the escallator chain to be c osed when the chain is moved in one direction upon closure of said potential switch and to be automatically opened by reverse movement of said chain with the potential switch closed. Y

15. An escalator having a conveyer memher, an electric motor to move it, a potential switch governing the circuit of said motor, a holding dog for said conveyer member normally disengaged therefrom, an electromagnetto hold said dog in its disengaged position when the potential switch is closed, and a circuit controller co-operating with said chain and automatically opened by reverse movement of the chain with the potential switch in its closed position.

' 16. An escalator having in combination a ,conveyer member, a dog normally disengaged from said conveyer member, an electromagnet co-operating with said dog for maintaining it in its inoperative position while said electromagnct is energized, and a circuit controller responsive to reverse movement of said conveyer member while said dog isin its inoperative position to deenergize said electromagnet independently of said dog.

17. An escalator having in combination an upper and a lower sprocket, an endless chain running over said sprockets, a holding dog co-operating with said endless chain and normally disengaged therefrom,an electromagnet co-operating with said dog to maintain it in its disengaged position when said electromagnet is energized, means for moving said dog into engagement with said chain when the electromagnet is deenergized, anda circuit controller responsive to reverse movement of said chain to deenergize said electromagnet independently of said dog and while the latter is disengaged from said chain.

18. An escalator having in combination an endless escalator chain, upper and lower sprockets engaged by said chain, a pivoted dog normally disengaged from said chain, a stationary supporting member to which said dog is pivoted, a reciprocating actuating member for said dog, a spring to move said actuating member in one direction to move the dog into engagement with said chain, an electromagnet to move said actuating member in the opposite direction and'permit said dog to be disen agedfrom said chain, an electric motor or driving said sprockets and endless chain in one direction, and a circuit controller responsive to reverse movement of said chain to deenergize said electromagnet independentl of said dog.

In testimony whereo I have signed my name to this specification.

GEORGE E. WOODWARD. 

